Mark L. Shaughnessy

Method of dynamically establishing communication of incoming messages to one or more user devices presently available to an intended recipient

Method and apparatus for monitoring environmental conditions in a communication system

Method for providing communication services based on geographic location

Wireless communication system incorporating multicast addressing and method for use

Method for joining dispatch calls

Mutli-site group dispatch call method

Communication system to communication system gateway method and apparatus

Method for determining geographic relationships between communication units

Push-to-talk/cellular networking system

Method for providing communications within a geographic region